Compressor having capacity modulation assembly

Abstract

A compressor includes a shell assembly, first and second scroll members and a capacity modulation assembly. The first and second scroll members form a series of pockets. A first modulation port defined in the first scroll member is in communication with a first pocket. The capacity modulation assembly is in communication with the first modulation port and is operable in full, partial and first and second pulse width modulation (PWM) capacity modes. The full capacity mode includes the first modulation port isolated from a suction pressure region of the compressor, the partial capacity mode includes the first modulation port in communication with the suction pressure region, the first PWM capacity mode includes a capacity between full and partial capacity via PWM between the full and partial capacity modes and the second PWM capacity mode includes a capacity between full and zero capacity by providing PWM of the capacity modulation assembly.

What is claimed is: 
     
       1. A compressor comprising:
 a shell assembly defining a suction pressure region and a discharge pressure region; 
 a first scroll member supported within said shell assembly and including a first end plate having a discharge passage, a first spiral wrap extending from said first end plate and a first modulation port extending through said first end plate; 
 a second scroll member supported within said shell assembly and including a second end plate having a second spiral wrap extending therefrom, said first and second spiral wraps meshingly engaged and forming a series of pockets during orbital displacement of said second scroll member relative to said first scroll member, said first modulation port being in communication with a first of said pockets; and 
 a capacity modulation assembly located within said shell assembly, in communication with said first modulation port and operable in:
 a full capacity mode with said first modulation port isolated from a suction pressure region of the compressor to operate the compressor at a full capacity; 
 a partial capacity mode with said first modulation port in communication with said suction pressure region to operate the compressor at partial capacity between the full capacity and zero capacity; 
 a first pulse width modulation capacity mode to operate the compressor at a first intermediate capacity between the full capacity and the partial capacity by providing pulse width modulated control of said capacity modulation assembly by switching between the full capacity mode and the partial capacity mode; and 
 a second pulse width modulation capacity mode to operate the compressor at a second intermediate capacity between the full capacity and zero capacity by providing pulse width modulated control of said capacity modulation assembly. 
 
 
     
     
       2. The compressor of  claim 1 , further comprising a seal assembly engaged with said shell assembly and first scroll member and isolating said discharge pressure region from said suction pressure region, said first end plate defining a biasing passage in communication with a second of said pockets formed by said first and second spiral wraps, said capacity modulation assembly including:
 a modulation valve ring located axially between said seal assembly and said first end plate and being in sealing engagement with an outer radial surface of an annular hub extending from said first end plate and said seal assembly to define an axial biasing chamber in fluid communication with said biasing passage, said modulation valve ring being axially displaceable between first and second positions, said modulation valve ring abutting said first end plate and closing said first modulation port when in the first position and being displaced axially relative to said first end plate and opening said first modulation port when in the second position; 
 a modulation lift ring located axially between said modulation valve ring and said first end plate and being in sealing engagement with said modulation valve ring to define a modulation control chamber; and 
 a modulation control valve assembly operable in first and second modes and in fluid communication with said modulation control chamber, said modulation control valve assembly controlling an operating pressure within said modulation control chamber and providing a first pressure within said modulation control chamber when operated in the first mode to displace said modulation valve ring to the first position and operate the compressor in the full capacity mode and providing a second pressure within said modulation control chamber greater than the first pressure when operated in the second mode to displace said modulation valve ring to the second position and operate the compressor in the partial capacity mode. 
 
     
     
       3. The compressor of  claim 2 , wherein the first pressure is a suction pressure within the compressor and the second pressure is an operating pressure within said biasing chamber. 
     
     
       4. The compressor of  claim 1 , wherein said capacity modulation assembly is operable in an unloaded mode to operate the compressor at approximately zero capacity during orbital displacement of said second scroll member relative to said first scroll member. 
     
     
       5. The compressor of  claim 4 , further comprising a seal assembly engaged with said shell assembly and said first scroll member and isolating said discharge pressure region from said suction pressure region, said first end plate including a biasing passage in communication with a second of said pockets and a biasing chamber defined by said seal assembly and said first scroll member, said capacity modulation assembly providing communication between said biasing chamber and said suction pressure region during the unloaded mode. 
     
     
       6. The compressor of  claim 5 , wherein the second pulse width modulation capacity mode includes compressor operation at a capacity between the full capacity mode and the unloaded mode by providing pulse width modulation of the capacity modulation assembly. 
     
     
       7. The compressor of  claim 6 , wherein the compressor is operated in the second intermediate capacity by pulse width modulation of the capacity modulation assembly between the full capacity mode and the unloaded mode. 
     
     
       8. The compressor of  claim 6 , wherein the second pulse width modulation capacity mode includes compressor operation at a capacity between the partial capacity mode and the unloaded mode. 
     
     
       9. The compressor of  claim 8 , wherein the compressor is operated in the second intermediate capacity by pulse width modulation of the capacity modulation assembly between the partial capacity mode and the unloaded mode. 
     
     
       10. The compressor of  claim 6 , wherein the capacity modulation assembly includes:
 a modulation valve ring located axially between said seal assembly and said first end plate and being in sealing engagement with an outer radial surface of an annular hub of said first scroll member and said seal assembly to define an axial biasing chamber in fluid communication with said biasing passage, said modulation valve ring being axially displaceable between first and second positions, said modulation valve ring abutting said first end plate and closing said first modulation port when in the first position and being displaced axially relative to said first end plate and opening said first modulation port when in the second position; 
 a modulation lift ring located axially between said modulation valve ring and said first end plate and being in sealing engagement with said modulation valve ring to define a modulation control chamber; and 
 a modulation control valve assembly operable in first and second modes and in fluid communication with said modulation control chamber, said modulation control valve assembly controlling an operating pressure within said modulation control chamber and providing a first pressure within said modulation control chamber when operated in the first mode to displace said modulation valve ring to the first position and operate the compressor in the full capacity mode and providing a second pressure within said modulation control chamber greater than the first pressure when operated in the second mode to displace said modulation valve ring to the second position and operate the compressor in the partial capacity mode. 
 
     
     
       11. The compressor of  claim 10 , wherein the first pressure is a suction pressure within the compressor and the second pressure is an operating pressure within said biasing chamber. 
     
     
       12. The compressor of  claim 10 , wherein the modulation control valve assembly includes a first valve in communication with said modulation control chamber and said biasing chamber and operable in an open and a closed position for selective communication between said modulation control chamber and said biasing chamber and a second valve in communication with said modulation control chamber and said suction pressure region and operable in an open and a closed position for selective communication between said modulation control chamber and said suction pressure region. 
     
     
       13. The compressor of  claim 12 , wherein the compressor is operating in the full capacity mode when said first valve is closed and said second valve is open. 
     
     
       14. The compressor of  claim 12 , wherein the compressor is operating in the partial capacity mode when said first valve is open and said second valve is closed. 
     
     
       15. The compressor of  claim 12 , wherein the compressor is operating in the unloaded mode when said first and second valves are open. 
     
     
       16. The compressor of  claim 12 , wherein the compressor is operating in the first pulse width modulated capacity mode or the second pulse width modulated capacity mode when one of said first and second valves are pulse width modulated. 
     
     
       17. The compressor of  claim 1 , wherein the partial capacity is a fixed capacity between the full capacity and zero capacity. 
     
     
       18. The compressor of  claim 1 , wherein the first intermediate capacity is a variable capacity between the full capacity and the partial capacity. 
     
     
       19. The compressor of  claim 1 , wherein the second intermediate capacity is a variable capacity between the full capacity and zero capacity. 
     
     
       20. In a compressor comprising a shell assembly defining a suction pressure region and a discharge pressure region, a first scroll member supported within said shell assembly and including a first end plate having a discharge passage, a first spiral wrap extending from said first end plate, and a second scroll member supported within said shell assembly and including a second end plate having a second spiral wrap extending therefrom, a capacity modulation assembly located within said shell assembly includes a first valve, a second valve, a first modulation port, a biasing chamber and a modulation control chamber and operates in a substantially full capacity, a partial capacity and an intermediate capacity to operate the compressor at a capacity between the full capacity and zero capacity;
 said first valve operates in an open and a closed position for selective communication between said modulation control chamber and said biasing chamber; 
 said second valve operates in an open and a closed position for selective communication between said modulation control chamber and said suction pressure region; 
 said first modulation port extends through said first end plate of said first scroll; 
 said biasing chamber biases said first and second spiral wraps into meshing engagement to form a series of pockets during orbital displacement of said second scroll member relative to said first scroll member at said full capacity; and 
 said modulation control chamber selectively operates at a pressure between a higher pressure and a lower pressure to limit communication between a first of said pockets and said suction pressure region through said first modulation port in said full capacity and to provide communication between said first of said pockets and said suction pressure region through said first modulation port in said partial capacity. 
 
     
     
       21. The compressor of  claim 20 , wherein said first valve is in communication with said suction pressure region and provides communication between said biasing chamber and said suction pressure region and said biasing chamber to operate the compressor at approximately zero capacity. 
     
     
       22. The compressor of  claim 21 , wherein said modulation control chamber is in communication with said suction pressure region to operate the compressor at approximately zero capacity. 
     
     
       23. The compressor of  claim 22 , wherein said first valve is in communication with said second valve and said first valve is in communication with said suction pressure region via said second valve to operate the compressor at approximately zero capacity. 
     
     
       24. The compressor of  claim 21 , wherein said intermediate capacity is provided by a pulse width modulation capacity mode including pulse width modulated control of at least one of said first and second valves to operate the compressor at the intermediate capacity. 
     
     
       25. The compressor of  claim 20 , wherein the intermediate capacity is a capacity between the full capacity and the partial capacity and said intermediate capacity is provided by a pulse width modulation capacity mode including pulse width modulated control of at least one of said first and second valves to operate the compressor at the intermediate capacity. 
     
     
       26. The compressor of  claim 20 , wherein said partial capacity provides a fixed capacity between the full capacity and zero capacity. 
     
     
       27. The compressor of  claim 20 , wherein the intermediate capacity includes a variable capacity between the full capacity and zero capacity.